The embodiments described herein relate generally to the field of medical detection systems for patients experiencing seizures. “A seizure is an abnormal, unregulated electrical charge that occurs within the brain's cortical gray matter and transiently interrupts normal brain function.” The Merck Manual of Diagnosis and Therapy, 1822 (M. Beers Editor in Chief, 18th ed. 2006) (“Merck Manual”). Epilepsy is a chronic disease characterized by such seizures, but not caused by an event such as a stroke, drug use or physical injury. Seizures may vary in frequency and scope and may range from involving no impairment of consciousness at all to complete loss of consciousness. Typically, a seizure resolves within a few minutes and extraordinary medical intervention, other than that needed for the comfort of the patient and to promote unobstructed breathing, is not needed. (See, generally, Merck Manual at 1822-1827, incorporated herein by reference.)
But in some cases, a seizure may lead to death. Asphyxia is an impairment or absence of the oxygen and carbon dioxide exchange in the body, which can occur, for example, during suffocation. Asphyxia is considered to be the leading cause of Sudden Unexplained Death in Epileptic Patients (“SUDEP”) and may indeed trigger SUDEP. But the mechanism and relationship of SUDEP with cardiorespiratory and cerebral function has been poorly understood. SUDEP does not occur during or, generally, immediately after an initial phase of a seizure but as the patient appears to be recovering from the seizure. In addition, SUDEP may occur at night, while the patient is sleeping. Such sudden unexplained death is not necessarily limited to seizure patients and may be underreported in the general population. But seizure patients, including those with epilepsy, seem to be at a higher risk for sudden unexplained death than the general population.
In a typical seizure condition, there are three phases: ictal, post ictal (or “postictal”), and interictal. The ictal phase is the initial portion of the seizure, where a patient may display symptoms, if any, such as convulsions. Generally speaking, the interictal phase is the period between seizures when the patient has substantially recovered.
A postictal phase takes place immediately after the ictal phase of the seizure, where symptoms have subsided, but the patient has not yet returned to normal. During the postictal period, the patient may be relaxed or lying down and may appear to be sleeping. In the postictal period, the patient's heart rate may typically take a few minutes to return to the patient's non-seizure baseline. The same is true of the patient's electrocardiogram (“EKG” or “ECG”) measurements, if the patient should happen to be undergoing EKG testing at the time of the seizure. EKG measurements provide a record of the heart's integrated action over a period of time. Cardiac and respiratory readings for the patient soon appear to be normal as the patient progresses in the postictal period. Such measurements and readings, along with visual observation, would support a view that a patient is coming out of the seizure in a normal fashion and is not at risk for SUDEP. One might thus conclude that no medical intervention is necessary. But in some cases, such measurements, readings and observations would be deceptive and the patient is at risk of SUDEP.
If a condition in a patient that leads to an increased risk of SUDEP can be detected, timely measures may be taken that would reduce that risk and possibly save the patient.
Accordingly, a need is present for methods, systems and apparatuses to detect one or more conditions in a patient that may lead to SUDEP and/or overcome issues discussed above.